public GeoElement[] processFunctionNVar(ExpressionNode funNode, FunctionNVar fun) {
fun.initFunction();
String label = fun.getLabel();
GeoElement[] ret = new GeoElement[1];
GeoElement[] vars = fun.getGeoElementVariables();
boolean isIndependent = (vars == null || vars.length == 0);
if (isIndependent) {
ret[0] = kernel.FunctionNVar(label, fun);
} else {
ret[0] = kernel.DependentFunctionNVar(label, fun);
}
return ret;
}
/**
* Evaluates this function using the given CAS command. Caching is used for symbolic CAS
* evaluations.
*
* @param ggbCasCmd the GeoGebraCAS command needs to include % in all places where the function f
* should be substituted, e.g. "Derivative(%,x)"
* @param symbolic true for symbolic evaluation, false to use values of GeoElement variables
* @return resulting function
*/
public final FunctionNVar evalCasCommand(String ggbCasCmd, boolean symbolic) {
// remember expression and its CAS string
boolean useCaching = true;
// for multi-variate functions we need to ensure value form,
// i.e. f(x,m)=x^2+m, g(x)=f(x,2), Derivative[g] gets sent as Derivative[x^2+2] instead of
// Derivative[f(x,2)]
// see http://www.geogebra.org/trac/ticket/1466
symbolic = symbolic && !expression.containsObjectType(GeoFunctionNVar.class);
// make sure to use temporary variable names
// e.g. a in Derivative[a*x^2,x] needs to be renamed temporarily when a exists in GeoGebra
// see http://www.geogebra.org/trac/ticket/929
boolean oldTempVariableValue = kernel.isUseTempVariablePrefix();
kernel.setUseTempVariablePrefix(true);
// did expression change since last time?
if (casEvalExpression != expression) {
casEvalExpression = expression;
if (symbolic) {
casEvalStringSymbolic = expression.getCASstring(ExpressionNode.STRING_TYPE_GEOGEBRA, true);
}
// caching should only be done if the expression doesn't contain
// other functions
// e.g. this is important for f(x) = x^2, g(x,y) = f(x) + y,
// Derivative(g(x,y), x)
// where we cannot cache the derivative of g because g may have
// changed
useCaching = symbolic && !expression.containsObjectType(CasEvaluableFunction.class);
}
// build command string for CAS
String expString =
symbolic
? casEvalStringSymbolic
: expression.getCASstring(ExpressionNode.STRING_TYPE_GEOGEBRA, false);
// set back kernel
kernel.setUseTempVariablePrefix(oldTempVariableValue);
// substitute % by expString in ggbCasCmd
String casString = ggbCasCmd.replaceAll("%", expString);
FunctionNVar resultFun = null;
// eval with CAS
try {
if (useCaching) {
// check if result is in cache
resultFun = lookupCasEvalMap(casString);
if (resultFun != null) {
// System.out.println("caching worked: " + casString + " -> " + resultFun);
return resultFun;
}
}
// evaluate expression by CAS
String result =
symbolic
? kernel.evaluateGeoGebraCAS(casString)
: // symbolic
kernel.evaluateCachedGeoGebraCAS(casString); // value string
// System.out.println("evaluateGeoGebraCAS: " + casString + " -> " + result);
// parse CAS result back into GeoGebra
sb.setLength(0);
sb.append("f("); // this name is never used, just needed for parsing
sb.append(getVarString());
sb.append(") = ");
sb.append(result);
// parse result
if (getVarNumber() == 1) {
resultFun = kernel.getParser().parseFunction(sb.toString());
} else {
resultFun = kernel.getParser().parseFunctionNVar(sb.toString());
}
resultFun.initFunction();
} catch (Error err) {
err.printStackTrace();
resultFun = null;
} catch (Exception e) {
e.printStackTrace();
resultFun = null;
} catch (Throwable e) {
resultFun = null;
}
// cache result
if (useCaching && resultFun != null) {
getCasEvalMap().put(casString, resultFun);
}
// System.out.println("NO caching: " + casString + " -> " + resultFun);
return resultFun;
}
